Witness History

In 1985, British scientists made what would turn out to be one of the most important environmental discoveries of the 20th century - finding a hole in the earth’s ozone layer.The British Antarctic Survey, based in Cambridge, had been monitoring ozone levels for more than 30 years using the Dobson Ozone Spectrophotometer.But it was only when they compared previously uncharted figures from the 1980s with the previous decade that they made the shocking finding, as Jonathan Shanklin, the man who compiled the data, told Jane Wilkinson.(Photo: Ozone hole in September 2006. Credit: Universal History Archive/Universal Images Group via Getty Images)

In February 1990, Nasa space probe Voyager took a famous photo of Earth as it left the Solar System.Seen from six billion kilometres away, our planet appears as a mere dot lit up by the sun, giving a sense of humanity's small place in the universe.In 2020, Darryl Morris spoke to Nasa planetary scientist Candice Hansen, who worked on the Voyager programme. A Made in Manchester production for BBC World Service.(Photo: Earth - a pale blue dot. Credit: Nasa/JPL-Caltech)

In 1982, after a two-year global search, the BBC auditioned Ken Hom to be the star of a new Chinese cookery TV series.In the show, called Ken Hom's Chinese Cookery, he introduced viewers to dishes like dim sum and spicy braised aubergine. He also gave advice on choosing and using a wok.He tells Josephine McDermott about his sudden rise to celebrity and how he brought Chinese dishes to new audiences. (Photo: Ken Hom. Credit: Chris Ridley/Radio Times/Getty Images)

It’s one of the most popular dishes in South East Asian cooking and for many it’s seen as Thailand’s national dish. However, the origins of pad Thai are disputed. Some believe it was created and taken to the country centuries ago by Chinese immigrants. Others believe it was invented during the rule of military dictator, Plaek Phibunsongkhram, as a way of cementing Thai nationalism in the 1940s. Thai food writer Chawadee Nualkhair dissects all the theories with Matt Pintus.(Photo: Pad Thai. Credit: Getty Images)

In 1994, biotech company Calgene brought the world's first genetically-modified food to supermarket shelves.The Flavr Savr tomato kept fresh for 30 days and could be shipped long distances without going off.Yet the world was wary of this new food, and it took 10 years and $100m of investment to get it to market.In 2017, the firm's then-CEO Roger Salquist told Claire Bowes about his mission to revolutionise the world's food.(Photo: Roger Salquist with a crop of Flavr Savrs. Credit: Richard Gilmore)

The kiwi fruit is synonymous with New Zealand in the minds of most European and American shoppers.But the hairy fruit actually comes from China and was once known as the Chinese gooseberry. So how did New Zealand hijack a Chinese fruit and turn it into their biggest horticultural export? Former fruit exporter Don Turner tells Vicky Farncombe how his family named the kiwi fruit in the 1950s and created a global industry.

In 1946, Italian confectioner Pietro Ferrero set out to bring chocolate to the masses. His recipe evolved over the years to become a world-famous product.Thomas Chatenier from the manufacturer tells Uma Doraiswamy how the chocolate and hazelnut formula spread across the globe.(Photo: The famous spread. Credit: Robert Gauthier/Los Angeles Times/Getty Images)

In the 1960s, the singer Dafydd Iwan started campaigning for the Welsh language to gain official status in Wales. For years, Dafydd received little support. In January 1969 he decided to up the pressure, defacing a police station sign written in English with paint. He ended up in prison, but soon young people across the country were picking up paint pots and taking up the cause. Today, the Welsh language is found in schools, on documents and on police station signs. Dafydd tells Anoushka Mutanda-Dougherty about his activism and singing.(Photo: Dafydd after his release from Cardiff prison. Credit: Central Press/Getty Images)

In 2014 three journalists were sentenced to seven years in jail in Egypt.Peter Greste, Mohammed Fahmy and Baher Mohamed became known as the Al Jazeera Three.The jail terms handed out to them led to an international outcry as protesters called for press freedom.Peter Greste tells his compelling story to Gill Kearsley.(Photo: Peter Greste inside the defendants’ cage. Credit: Khaled Desouki/AFP via Getty Images)

In late 1973, Chile was in turmoil. General Augusto Pinochet had led a military coup deposing the socialist president Salvador Allende who was now dead.The army was rounding up leftists; torturing, imprisoning and killing them.In the capital Santiago, the country’s best-known poet Pablo Neruda was lying in a hospital bed. He was 69 and had cancer.As a prominent member of the Communist Party his life was in danger. He had to get out.With him was his driver and personal assistant Manuel Araya who spoke to Gideon Long.(Photo : The poet in 1963. Credit: Angelo Cozzi/Mondadori/Getty Images)